镍基单晶高温合金中温稳态蠕变期间的变形机制  

DEFORMATION MECHANISMS OF Ni-BASED SINGLE CRYSTAL SUPERALLOYS DURING STEADY-STATE CREEP AT INTERMEDIATE TEMPERATURES

作　　者：苏勇[1,2] 田素贵[1] 于慧臣[3] 于莉丽[1] 

机构地区：[1]沈阳工业大学材料科学与工程学院,沈阳110870 [2]沈阳化工大学能源与动力工程学院,沈阳110142 [3]中航工业北京航空材料研究院航空材料检测与评价北京市重点实验室,先进高温结构材料国防科技重点实验室,北京100095

出　　处：《金属学报》2015年第12期1472-1480,共9页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目51271125;辽宁省教育厅项目L2015426资助~~

摘　　要：通过蠕变性能测试、组织形貌观察及位错组态的衍射衬度分析,研究了镍基单晶高温合金在中温/高应力稳态蠕变期间的变形机制.结果表明,在760℃,760 MPa和800℃,650 MPa蠕变期间,剪切g′相的位错可发生分解,分解后领先的a/3<112>超点阵Shockley不全位错切入g′相,拖曳的a/6<112>Shockley不全位错滞留在g′/g相界面,2个不全位错之间形成超点阵内禀堆垛层错(SISF);此外,剪切进入g′相的超点阵位错可由{111}面交滑移至{100}面,形成具有非平面位错芯结构的K-W锁,可抑制位错的滑移和交滑移,提高合金的蠕变抗力.在850℃,500 MPa蠕变期间,合金中的层错消失,部分剪切进入筏状g′相的a<110>超点阵位错可分解形成"2个a/2<110>不全位错加反相畴界(APB)"的组态,而合金中K-W锁的消失是由高温热激活致使立方体滑移的位错重新交滑移至八面体所致.Ni-based single crystal （SC） superalloys have been widely used to produce turbine blades of aero- engines, but under the action of centrifugal force, creep damage is still the main failure mode. In service, the blades experience multiple cycles of various conditions of high temperatures, low stresses and intermediate temperatures, high stresses, and due to effective and efficient means of cooling and insulating the blades during operation, the ac- tual temperature the blades bear can be smaller than the working temperature at the hot ends of aeroengines, so the systematical study on the creep behavior of SC superalloys at intermediate temperatures, high stresses is significant. It is generally considered that dislocations cutting γ′ phase is the main deformation mechanism of SC alloys at intermediate temperatures, high stresses, and dislocations cutting into γ′phase can be decomposed into different configurations for different alloy systems, even under similar conditions. Moreover, large amount of dislocations cutting into γ′ phase means the degradation of creep performance of the alloys, so it is significant to study the cutting modes of dislocations. In this work, by means of creep tests, TEM observations and diffraction contrast analysis of dislocations, the deformation mechanisms of a Ni-based SC superalloy during steady-state creep at intermediate temperatures, high stresses are studied. Results show that, under the conditions of 760 ℃, 760 MPa and 800 ℃, 650 MPa, dislocations cutting into y phase are decomposed to form partial dislocations plus superlattice intrinsic stacking faults （SISF）. Thereinto, the leading a/3〈112〉 super Shockley partial dislocations cut into γ′ precipitates, while the dragging a/6〈112〉 Shockley partial dislocations remain at γ′/γ interfaces, and between them there exists SISF. Additionally, super dislocations shearing into y phase can cross slip from {111 } to {100} crystal planes to form Kear-Wilsdorf （K-W） locks with non-plane dislocation co

关 键 词：镍基单晶合金 蠕变 位错 层错 变形机制 

分 类 号：TG132.3[一般工业技术—材料科学与工程]